1. Field of the Invention
The present invention relates to a fuel cell.
2. Description of the Related Art
Hitherto, there has been widely known a fuel cell which is a fired body including a porous plate-like support substrate having gas flow paths formed therein, and a power generation element part which is provided on a principal surface of the support substrate and in which at least a fuel electrode, a solid electrolyte, and an air electrode are laminated in this order (see, for example, Japanese Patent Application Laid-Open Nos. Hei 8-106916 and 2008-226789).
The above-mentioned fuel cell is produced, for example, in the following procedure. First, a compact (green film) of the fuel electrode and a compact of the solid electrolyte are laminated successively on a principal surface of a compact of the support substrate. The laminated compacts are co-fired in the atmosphere. A compact of the air electrode is laminated on a surface of the solid electrolyte in the laminated fired body. The compact of the air electrode is fired in the atmosphere, and thus the fuel cell is produced as a fired body. After that, in order to acquire conductivity of the support substrate, the fuel electrode, and the like, before the fuel cell is operated, the fuel cell as a fired body is subjected to heat treatment (hereinafter referred to as “reducing treatment”) involving supplying reducing gas at a high temperature (for example, about 800° C.) to the fuel cell, and thus the fuel cell is shifted from a non-reductant to a reductant.